Underground water conduits, either potable water pipes, waste water pipes or sewer pipes, are typically made of rigid materials such as reinforced concrete, cast iron, ductile iron, steel and hard polymers such as PVC, HDPE, etc. that are durable and adapted to resist high internal pressure if required and the weight of the landfill covering them. Underground water pipes provide essential services to the urban population, and as a result of their geographical dispersion they remain particularly vulnerable to damage caused by natural disasters. A network of buried water pipes connected together extends over long distances, spreads out in all directions to provide services to residential home or businesses over a wide area and may pass through soils having different properties.
In the event of an earthquake or a landslide, the network of water pipes is subjected to variable ground motions along its various segments and particularly at its various connections for which it may not have been designed to resist. For example, at bends, elbow or tee connections, seismic waves propagating in a certain direction or landslides moving in a certain direction, affect the water pipes before and after bends, elbow or tee connections differently. Previous major earthquakes revealed that most damage of the buried segmented water pipes occurs at the joints and connections of the network of water pipes. It has been proven that the differential motions between the pipe segments are one of the primary reasons that results in damages and ruptures. With the surrounding soil giving way, the external forces exerted on the water pipe network around bends, elbow and tee connections and around straight couplings connecting abutting pipe segments generate high shear and tensile stresses and strains that often exceed the elastic limits of the pipes or the pipes connections leading to multiple ruptures in the network of water pipes at various points thereby partially or completely shutting down water supply to residential home and/or businesses over the area serviced by the water network.
Functioning water systems are a cornerstone of urban human communities, to bring in the clean water on demand for drinking, washing and sanitary needs, and in turn remove the used water from drains, waste, and storm water sources. If the water network system is suddenly rendered partially or totally non-functional by an earthquake or a landslide, critical disruption of the community and public health danger may result. In catastrophic events such as earthquakes, water supply to the population in the aftermath of the event is crucial and must be restored rapidly. However, locating and replacing ruptured or broken pipe segments and pipe connections through a vast network is time consuming and requires heavy machinery for excavation, removal of damage pipes and connections and installation of new pipes and connections.
Newer networks of underground water conduits built in high risk areas are designed to withstand higher shear and tensile stresses and strains such as those generated by earthquakes and landslides. However, the vast majority of underground water networks were built many decades ago based on lower standards and cannot withstand the high shear and tensile stresses and strains generated by earthquakes and landslides.
Replacing older networks of underground water conduits with new ones more adapted to withstand the high shear and tensile stresses and strains generated by earthquakes and landslides is unrealistic because of the sheer magnitude of the work that would be involved. However, reinforcing existing water networks without the need to excavate represents a feasible alternative especially in higher risk areas.
Therefore, there is a need for a method of reinforcing underground water conduits to resist earthquakes and landslides and to a reinforcement structural device adapted for insertion into underground water conduits without having to excavate.